Risk of ectopic pregnancy and previous induced abortion.

OBJECTIVES: This study investigated the role of prior history of induced abortion in subsequent ectopic pregnancies. METHODS: Data from two French case-control studies were used to examine the effect of induced abortion on ectopic pregnancy risk. Case patients (n = 570) were women admitted for ectopic pregnancy during the study period; controls (n = 1385) were women who delivered in the same center. RESULTS: The analysis among women with no previous ectopic pregnancy showed that, after control for the main ectopic pregnancy risk factors, prior induced abortion was associated with an increased risk of ectopic pregnancy (odds ratio [OR] = 1.5, 95% confidence interval [CI] = 1.0, 2.0); there was a significant trend between number of previous induced abortions and ectopic pregnancy risk (ORs = 1.4 for 1 previous induced abortion and 1.9 for 2 or more). CONCLUSIONS: This study suggests that induced abortion may be a risk factor for ectopic pregnancy for women with no previous ectopic pregnancy, particularly in the case of women who have had several induced abortions.     

Induced abortion and the risk of subsequent ectopic pregnancy.

This study assessed the effect of legal induced abortion on ectopic pregnancy risk by using a comparison group of reproductive-age women who were at risk of becoming pregnant during the same time period the women with ectopic pregnancy conceived. Cases were members of Group Health Cooperative of Puget Sound who were hospitalized for ectopic pregnancy from October 1981 through September 1986 (N = 211). Controls were randomly selected members matched to cases on age and county of residence (N = 457). All subjects in this analysis had had one or more prior pregnancies. Eighty-eight cases (41.7 per cent) and 177 controls (38.7 per cent) had a history of one or more induced abortions. The relative risk of ectopic pregnancy associated with one abortion was 0.9 (95 per cent confidence interval 0.6, 1.3), adjusted for age, county, reference date, religion, gravidity, age at first pregnancy, lifetime number of sexual partners, and miscarriage history. Among women with two or more prior pregnancies, the risk associated with two or more abortions was 1.2 (0.6, 2.4). Controlling for pelvic inflammatory disease and use of intrauterine devices did not alter these risks. We conclude that legal abortion as performed in the US since 1970 has little or no influence on a woman's risk of ectopic pregnancy in subsequent pregnancies.     

Ectopic pregnancy and prior induced abortion.

We compared the prior pregnancy histories of 85 multigravid women with an ectopic pregnancy and 498 multigravid delivery comparison subjects. We found a relationship between the number of prior induced abortions and the risk of ectopic pregnancy: the crude relative risk of ectopic pregnancy was 1.6 for women with one prior induced abortion and 4.0 for women with two or more prior induced abortions; however, use of multivariate techniques to control confounding factors reduced the relative risks to 1.3 (95 per cent confidence interval, 0.6-2.7) and 2.6 (95 per cent confidence interval, 0.9-7.4), respectively. The analysis suggests that induced abortion may be one of several risk factors for ectopic pregnancy, particularly for women who have had abortions plus pelvic inflammatory disease or multiple abortions.     

Risk factors for ectopic pregnancy: a comprehensive analysis based on a large case-control,population-based study in France

This case-control study was associated with a regional register of ectopic pregnancy between 1993 and 2000 in France. It included 803 cases of ectopic pregnancy and 1,683 deliveries and was powerful enough to investigate all ectopic pregnancy risk factors. The main risk factors were infectious history (adjusted attributable risk = 0.33; adjusted odds ratio for previous pelvic infectious disease = 3.4, 95% percent confidence interval (CI): 2.4, 5.0) and smoking (adjusted attributable risk = 0.35; adjusted odds ratio = 3.9, 95% CI: 2.6, 5.9 for >20 cigarettes/day vs. women who had never smoked). The other risk factors were age (associated per se with a risk of ectopic pregnancy), prior spontaneous abortions, history of infertility, and previous use of an intrauterine device. Prior medical induced abortion was associated with a risk of ectopic pregnancy (adjusted odds ratio = 2.8, 95% CI: 1.1, 7.2); no such association was observed for surgical abortion (adjusted odds ratio = 1.1, 95% CI: 0.8, 1.6). The total attributable risk of all the factors investigated was 0.76. As close associations were found between ectopic pregnancy and infertility and between ectopic pregnancy and spontaneous abortion, further research into ectopic pregnancy should focus on risk factors common to these conditions. In terms of public health, increasing awareness of the effects of smoking may be useful for ectopic pregnancy prevention.     

Induced abortion and breast cancer risk

Results from case-control studies suggest that induced abortion may be associated with a small increase in risk of breast cancer. While risk estimates from cohort studies have generally not observed such an association, these studies have had limited information regarding abortion and possible confounding variables. Therefore, we conducted a study among a cohort of post-menopausal women from whom detailed information regarding pregnancy outcomes as well as risk factors for breast cancer had been collected. The study sample included 37,247 Iowa Women's Health Study participants, 55-64 years of age at baseline in 1986, who reported no history of breast, or other, cancer (except non-melanoma skin cancer), and for whom information regarding pregnancy outcomes (that is, live birth, stillbirth, spontaneous abortion, ectopic pregnancy or induced abortion) was available. We used linkage with records of the State Health Registry of Iowa, part of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program, to estimate the incidence of breast cancer among cohort members through 1995. We calculated age-adjusted relative risks and 95% confidence intervals using Cox proportional hazards regression. Only 653 women (1.8%) reported an induced abortion. The age-adjusted relative risk of breast cancer among women with prior induced abortion compared with those without was 1.1 (95% CI = 0.8-1.6). Relative risks were higher among women whose age at first abortion was less than 20 or at least 30 years, for those whose abortion took place after their first birth or who never gave birth, and for those with early termination (0-2 months). These estimates varied from 1.3-1.7, but the confidence intervals around each were wide. Since most women in this cohort were beyond their reproductive years when abortion became legal in 1973, the low prevalence of induced abortion argues for a cautious interpretation.     

Abortion,changed paternity,and risk of preeclampsia in nulliparous women

A prior birth confers a strong protective effect against preeclampsia, whereas a prior abortion confers a weaker protective effect. Parous women who change partners in a subsequent pregnancy appear to lose the protective effect of a prior birth. This study (Calcium for Preeclampsia Prevention Trial, 1992-1995) examines whether nulliparous women with a prior abortion who change partners also lose the protective effect of the prior pregnancy. A cohort analysis was conducted among participants in this large clinical trial of calcium supplementation to prevent preeclampsia. Subjects were nulliparous, had one prior pregnancy or less, delivered after 20 weeks' gestation, and were interviewed at 5-21 weeks about prior pregnancies and paternity. Women without a history of abortion served as the reference group in logistic regression analyses. Women with a history of abortion who conceived again with the same partner had nearly half the risk of preeclampsia (adjusted odds ratio = 0.54, 95 percent confidence interval: 0.31, 0.97). In contrast, women with an abortion history who conceived with a new partner had the same risk of preeclampsia as women without a history of abortion (adjusted odds ratio = 1.03, 95 percent confidence interval: 0.72, 1.47). Thus, the protective effect of a prior abortion operated only among women who conceived again with the same partner. An immune-based etiologic mechanism is proposed, whereby prolonged exposure to fetal antigens from a previous pregnancy protects against preeclampsia in a subsequent pregnancy with the same father.     

Relations of gestational length and timing and type of incomplete pregnancy to ovarian cancer risk

While the protective nature of parity with respect to ovarian cancer has been well documented, whether a history of incomplete pregnancy affects ovarian cancer risk is uncertain. Data collected from 739 epithelial ovarian cancer cases and 1,313 community controls in the Delaware Valley from 1994 to 1998 were used to evaluate the relation between gestational length and timing of first induced or spontaneous abortion and ovarian cancer risk. Incomplete pregnancy was not associated with ovarian cancer among nulliparous women or among ever-pregnant women either before or after adjustment for relevant confounders (for nulliparous women, odds ratio (OR) = 1.12, 95% confidence interval (CI): 0.66, 1.89; for ever-pregnant women, OR = 0.95, 95% CI: 0.76, 1.18). Among unigravid women, one full-term pregnancy was more protective than an incomplete pregnancy (adjusted OR = 0.29, 95% CI: 0.15, 0.57). These results were independent of the type of pregnancy loss. Among ever-pregnant women, a spontaneous abortion before a first birth provided significant protection (adjusted OR = 0.47, 95% CI: 0.30, 0.75), while no significant effect was found for an induced abortion prior to a first birth (adjusted OR = 0.80, 95% CI: 0.44, 1.47). These data do not support an independent association between incomplete pregnancies, either spontaneous or induced, and ovarian cancer risk.     

Abortion and its effect on risk of preeclampsia and transient hypertension

We examined the effect of abortion type, number, and gestational age on the risk of preeclampsia and transient hypertension among women who received prenatal care from 13 obstetric practices in southern Connecticut between April 1988 and December 1991 (N = 2,739). Subjects were interviewed before 16 weeks' gestation regarding reproductive history and pregnancy-related risk factors. We estimated the risk of preeclampsia (N = 44) and transient hypertension (N = 172) among nulliparous women who had had one or more abortions, with nulliparous women with no abortion as the referent group. Similar effects were seen for one spontaneous or induced abortion, when analyzed separately. A single prior abortion was associated with a decreased risk of preeclampsia [odds ratio (OR) = 0.35; 95% exact confidence interval (CI) = 0.09-1.01]. One abortion had only a small association with risk of transient hypertension (OR = 1.09, 95% exact CI = 0.68-1.72); however, a history of two or more abortions was associated with a decreased risk (OR = 0.42, 95% exact CI = 0.16-0.94). Among nulliparous women with a history of one abortion, a decreased risk of both hypertensive disorders was observed among women whose aborted pregnancy ended at > or =3 months gestation. These findings suggest that a history of abortion in nulliparous women is a protective factor against the risk of preeclampsia in the subsequent pregnancy.     

Risk factors for ectopic pregnancy: a case-control study in France, with special focus on infectious factors

A case-control study was conducted in 1988 in seven Paris area maternity hospitals to evaluate the role of several risk factors, particularly infectious factors, in ectopic pregnancy. A total of 279 cases and 279 controls were compared for sociodemographic characteristics, cigarette smoking, sexual, reproductive and surgical histories, and conditions of conception. Pelvic inflammatory disease confirmed by celioscopy (odds ratio (OR) = 5.5, 95% confidence interval (CI) 2.1-13.9) and Chlamydia trachomatis seropositivity (OR = 3.9, 95% CI 2.3-6.7) appeared to be important risk factors for ectopic pregnancy. Other risk factors found to be associated with an increased risk of ectopic pregnancy were dose-related cigarette smoking at the time of conception (ORs 1.3 to 2.5), appendectomy (OR = 1.6, 95% CI 1.1-2.5), prior tubal surgery (OR = 5.1, 95% CI 1.7-15.4), induced conception cycle (OR = 3.2, 95% CI 1.1-9.3), and prior ectopic pregnancy (OR = 13.3, 95% CI 4.5-39.2). However, some of the latter risk factors, i.e., prior tubal surgery, prior ectopic pregnancy, and perhaps appendectomy, may be considered to be the results of pelvic inflammatory disease and sexually transmitted diseases. Maternal age, parity, prior induced abortion, and prior spontaneous abortion were not associated with ectopic pregnancy. Use of intrauterine device, progestagen micropill, and also combined estroprogestative pill at the time of conception were associated with a better prevention of intrauterine pregnancy than of ectopic pregnancy. These findings confirm the importance of several previously reported risk factors of ectopic pregnancy: sexually transmitted diseases, cigarette smoking, and prior ectopic pregnancy. They also identified new risk factors, appendectomy and induced conception cycle, and revealed that the combined estroprogestative pill does not prevent ectopic pregnancy as effectively as it does intrauterine pregnancy.     

Induced abortion: not an independent risk factor for pregnancy outcome, but a challenge for health counseling

PURPOSE: Low birth weight (LBW), preterm births, abnormal placentation, and miscarriages have been associated with prior induced abortions. An incidence-related effect has been suggested. The objective of this study is to assess the effects of prior induced abortions on obstetric risk factors and pregnancy outcome in conditions of free high-standard maternity care used by almost the entire pregnant population in Finland. METHODS: We analyzed a population-based database including 26,976 singleton pregnancies from 1989 to 2001, of which 2364 were among women with one prior induced abortion and 355 women had had at least two prior induced abortions. Data included maternal risk factors, pregnancy characteristics, and obstetric outcome measures and were based on results of a self-administered questionnaire at 20 weeks of pregnancy and clinical records. Odds ratios (ORs) concerning pregnancy outcomes were calculated in multiple logistic regression analysis. RESULTS: Induced abortions were associated with several known pregnancy risk factors; specifically, maternal age older than 35 years, unemployment, unmarried status, low educational level, smoking, alcohol consumption, overweight condition, and chronic illnesses. Preterm birth (OR, 1.19; 95% confidence interval, 1.01-1.41) in women with one prior abortion (7.3% versus 6.2%) and LBW (OR, 1.54; 95% confidence interval, 1.02-2.32) in women with two or more prior abortions (7.0% versus 4.7%) appeared to be more common, but after logistic regression analysis, we found no evidence of adverse pregnancy outcomes. CONCLUSIONS: Induced abortion is not an independent risk factor for adverse obstetric outcome. Marked health behavioral pregnancy risks are associated with prior induced abortions. Health counseling of these women is a challenge, but this objective has not yet been achieved.     

Mifepristone-induced abortion and vaginal bleeding in subsequent pregnancy

BackgroundThe aim of this study is to explore the effect of first-trimester mifepristone-induced abortion on vaginal bleeding in subsequent pregnancy.Study DesignThis observational cohort study was conducted during 1998–2001 at antenatal clinics in Beijing, Chengdu, and Shanghai, China. The study enrolled 4,931 women with one previous mifepristone-induced abortion, 4,925 women with no history of induced abortion, and 4,800 women with one previous surgical abortion and followed them through pregnancy and childbirth.ResultsThe rates of vaginal bleeding in pregnant women with a history of medical abortion, no abortion, and surgical abortion were 16.5%, 13.9%, and 17.3%, respectively. The women with medical abortion had a higher risk (adjusted relative risk (aRR)=1.17, 95% confidence interval (CI): 1.07, 1.29) of vaginal bleeding compared with those with no abortion but similar risk to prior surgical abortion. When the correlation between medical abortion and vaginal bleeding was examined by period, increased risk was observed only in the early period (<16 gestational weeks) (aRR=1.25, 95% CI: 1.12, 1.39). The comparison between subgroups of medical abortion and no abortion showed that the observed risks increased particularly in those with abortion at gestational age ≤7 weeks (aRR=1.33, 95% CI: 1.18, 1.49), those followed by a postabortion curettage (aRR=1.58, 95% CI: 1.37, 1.84) or complications (aRR=1.99, 95% CI: 1.67, 2.37). There was no difference between women with medical abortion and women with surgical abortion in the occurrence of vaginal bleeding for either period.ConclusionsOne previous mifepristone-induced abortion increased the risk of vaginal bleeding in early gestation period of subsequent pregnancy compared with no abortion, especially if abortion occurred before 7 weeks of gestation and was followed by a curettage or complications.     

Mifepristone-induced early abortion and outcome of subsequent wanted pregnancy

Follow-up information on subsequent pregnancies after mifepristone (RU486)-induced abortion is scarce. The authors examined whether one mifepristone-induced first-trimester abortion affects the outcome of a subsequent wanted pregnancy. In a study conducted in 1998-2001 at antenatal clinics in Beijing, Chengdu, and Shanghai, China, the authors enrolled 4,925 women with no history of induced abortion, 4,931 women with one previous mifepristone-induced abortion, and 4,800 women with one previous surgical abortion and followed them through pregnancy and childbirth. The adjusted odds ratio for preterm delivery in women with one mifepristone abortion compared with women with no abortion was 0.77 (95% confidence interval: 0.61, 0.98). Although the mean birth weight of infants born to women with mifepristone abortion was 33 g (95% confidence interval: 17, 49) higher than that of infants born to women with no abortion, the frequencies of low birth weight and mean lengths of pregnancy were similar. There were no significant differences in risk of preterm delivery, frequency of low birth weight, or mean infant birth weight in the comparisons of women with previous mifepristone abortion and women with surgical abortion. This study suggests that one early abortion induced by mifepristone in nulliparous women has no adverse effects on the outcome of a subsequent pregnancy.     

Mifepristone-induced abortion and vaginal bleeding in subsequent pregnancy

Background

The aim of this study is to explore the effect of first-trimester mifepristone-induced abortion on vaginal bleeding in subsequent pregnancy.

Study Design

This observational cohort study was conducted during 1998–2001 at antenatal clinics in Beijing, Chengdu, and Shanghai, China. The study enrolled 4,931 women with one previous mifepristone-induced abortion, 4,925 women with no history of induced abortion, and 4,800 women with one previous surgical abortion and followed them through pregnancy and childbirth.

Results

The rates of vaginal bleeding in pregnant women with a history of medical abortion, no abortion, and surgical abortion were 16.5%, 13.9%, and 17.3%, respectively. The women with medical abortion had a higher risk (adjusted relative risk (aRR)=1.17, 95% confidence interval (CI): 1.07, 1.29) of vaginal bleeding compared with those with no abortion but similar risk to prior surgical abortion. When the correlation between medical abortion and vaginal bleeding was examined by period, increased risk was observed only in the early period (<16 gestational weeks) (aRR=1.25, 95% CI: 1.12, 1.39). The comparison between subgroups of medical abortion and no abortion showed that the observed risks increased particularly in those with abortion at gestational age ≤7 weeks (aRR=1.33, 95% CI: 1.18, 1.49), those followed by a postabortion curettage (aRR=1.58, 95% CI: 1.37, 1.84) or complications (aRR=1.99, 95% CI: 1.67, 2.37). There was no difference between women with medical abortion and women with surgical abortion in the occurrence of vaginal bleeding for either period.

Conclusions

One previous mifepristone-induced abortion increased the risk of vaginal bleeding in early gestation period of subsequent pregnancy compared with no abortion, especially if abortion occurred before 7 weeks of gestation and was followed by a curettage or complications.     

Low birth weight in relation to multiple induced abortions.

BACKGROUND. Most studies report that a single induced abortion does not increase risk for delivering a low birth weight infant in a subsequent pregnancy. However, the effect of multiple abortions has not been adequately evaluated. METHODS. This relationship was studied in 6541 White women who delivered their first child between 1984 and 1987. We compared the frequencies of low birth weight (less than 2500 g) among infants born to 1999 women without prior induced abortion and 1999 women with one abortion with the frequencies of low birth weight among infants born to women with two (n = 1850), three (n = 520), and four or more (n = 173) prior induced abortions. RESULTS. After adjustment for confounding variables, we found no linear relationship in risk of low birth weight among women with one (relative risk [RR] = 1.2, 95% confidence interval [CI] = 0.9-1.5), two (RR = 1.5, 95% CI = 1.1-2.0), three (RR = 1.3, 95% CI = 0.8-1.9), or four or more (RR = 1.6, 95% CI = 0.9-2.9) prior induced abortions. CONCLUSIONS. These findings confirm earlier reports of little or no evidence of harmful effects on birth weight by one or by two or more induced abortions. We further report that risk is not significantly elevated even in women with three, four, or more prior terminations of pregnancy when compared with women with one or two abortions.     

Induced abortion as an independent risk factor for breast cancer: a comprehensive review and meta-analysis.

STUDY OBJECTIVE: To ascertain, from the published reports to date, whether or not a significantly increased risk of breast cancer is specifically attributable to a history of induced abortion, independent of spontaneous abortion and age at first full term pregnancy (or first live birth); to establish the relative magnitude of such risk increase as may be found, and to ascertain and quantify such risk increases as may pertain to particular subpopulations of women exposed to induced abortion; in particular, nulliparous women and parous women exposed before compared with after the first full term pregnancy. INCLUDED STUDIES: The meta-analysis includes all 28 published reports which include specific data on induced abortion and breast cancer incidence. Since some study data are presented in more than one report, the 28 reports were determined to constitute 23 independent studies. Overall induced abortion odds ratios and odds ratios for the different subpopulations were calculated using an average weighted according to the inverse of the variance. An overall unweighted average was also computed for comparison. No quality criteria were imposed, but a narrative review of all included studies is presented for the reader's use in assessing the quality of individual studies. EXCLUDED STUDIES: All 33 published reports including data on abortion and breast cancer incidence but either pertaining only to spontaneous abortion or to abortion without specification as to whether it was induced or spontaneous. These studies are listed for the reader's information. RESULTS: The overall odds ratio (for any induced abortion exposure; n = 21 studies) was 1.3 (95% confidence interval of 1.2, 1.4). For comparison, the unweighted overall odds ratio was 1.4 (1.3,1.6). The odds ratio for nulliparous women was 1.3 (1.0,1.6), that for abortion before the first term pregnancy in parous women was 1.5 (1.2,1.8), and that for abortion after the first term pregnancy was 1.3 (1.1,1.5). CONCLUSIONS: The results support the inclusion of induced abortion among significant independent risk factors for breast cancer, regardless of parity or timing of abortion relative to the first term pregnancy. Although the increase in risk was relatively low, the high incidence of both breast cancer and induced abortion suggest a substantial impact of thousands of excess cases per year currently, and a potentially much greater impact in the next century, as the first cohort of women exposed to legal induced abortion continues to age.     

Prior spontaneous abortion, prior elective termination, interpregnancy interval, and risk of neural tube defects

A woman with a history of spontaneous abortion in her immediately prior pregnancy may be at increased risk for a pregnancy affected by a neural tube defect (NTD). A short interpregnancy interval may further increase this risk. Using data from a population-based case-control study (1989-1991), the authors investigated NTD risk resulting from a prior spontaneous abortion or elective termination and a short interpregnancy interval. Of 538 interviewed case mothers and 539 interviewed control mothers, 408 case mothers and 433 control mothers reported having a prior pregnancy. Analysis showed a slightly decreased NTD risk among mothers whose immediately prior pregnancy had ended in a spontaneous abortion or elective termination in comparison with a live birth (odds ratio (OR) = 0.82; 95% confidence interval (CI): 0.61, 1.1). This decreased risk was consistent across strata of short or long interpregnancy intervals. Additional analysis revealed an increased NTD risk for mothers with an interpregnancy interval of < or =6 months compared with >12-< or =24 months (OR = 1.5; 95% CI: 0.93, 2.4). This latter risk was greatest among mothers whose immediately prior pregnancy had resulted in a live birth (OR = 2.0; 95% CI: 1.0, 3.8) rather than a spontaneous abortion or elective termination (OR = 0.96; 95% CI: 0.44, 2.1). Adjustment for potential covariates did not substantially alter observed risk estimates.     

基层宫内节育器避孕失败的高危因素调查

目的:探讨基层妇女使用宫内节育器(IUD)避孕失败的高危因素,为预防失败提供参考。方法:选取2012年5月~2013年5月本院就诊的放置IUD避孕失败的妇女100例作为观察组,用数字表法随机抽出同期采用IUD避孕正常的妇女100例作为对照组。调查两组妇女的基本情况,然后进行logistic回归分析,总结IUD避孕失败(包括IUD合并妊娠及IUD合并异位妊娠)的高危因素。结果:观察组和对照组在年龄、孕产史、月经情况、是否在哺乳期放置、IUD的类型、IUD位置、放置年限、施术者技术、子宫畸形、宫颈松紧度、既往流产史、是否有IUD下移或脱落史、是否合并其他妇科疾病以及是否规范随访等因素均存在统计学差异(P均0.05),经多因素非条件logistic回归分析,年龄、孕产史、月经过多、IUD的类型、IUD位置、放置年限、施术者、子宫畸形、宫颈松紧度、既往流产史、IUD下移或脱落史等因素的OR值分别为4.381、5.872、6.849、3.095、6.528、4.692、2.648、2.797、6.029、1.877和2.766,95%CI值分别为3.563~17.428、5.465~20.593、6.257~25.497、2.184~9.546、6.007~24.270、4.183~18.749、1.755~6.490、1.953~8.589、5.746~22.834、1.269~4.554和1.921~8.294;IUD合并异位妊娠与IUD合并妊娠妇女在IUD类型、放置年限、施术者、合并盆腔炎、合并子宫肌瘤或内膜息肉、月经过多、既往流产史等方面均存在统计学差异(P0.05),经多因素非条件logistic回归分析,IUD类型、放置年限、施术者技术、合并盆腔炎、合并子宫肌瘤或内膜息肉、月经过多、既往流产史等因素的OR值分别为5.294、4.158、6.569、8.978、8.015、10.187和6.259,95%CI值分别为5.347~21.865、3.752~14.691、6.104~27.384、9.403~36.036、8.927~32.968、10.953~42.581和6.463~26.557。结论:年龄、孕产史、月经过多、IUD的类型及型号、IUD位置、放置年限、施术者技术、子宫畸形、宫颈松紧度、既往流产史、有IUD下移或脱落史等因素为IUD避孕失败的高危因素;IUD类型、放置年限、施术者技术、月经过多、既往流产史等为IUD合并异位妊娠的高危因素,合并盆腔炎、合并子宫肌瘤或内膜息肉可能为IUD合并异位妊娠的高危因素。     

Induced abortion in relation to breast cancer among parous women: a birth certificate registry study

We wished to assess the relation of induced abortion to the subsequent incidence of breast cancer among parous women, using a design that would prevent the possibility of differentially complete reporting of abortion history by women with breast cancer and controls. Our study was conducted within a cohort of women who gave birth to a child during 1984-1994 while residing in 13 counties of western Washington. Cases were women from the cohort diagnosed with breast cancer between 1984 and 1994. From the remaining cohort members, five controls were matched to each woman with breast cancer by year of index birth (ie, the last child born before breast cancer diagnosis) and by age at delivery. We categorized 463 cases and 2,201 controls according to history of induced abortion as recorded on the index birth certificate. The risk of breast cancer was not found to be associated with a prior induced abortion (estimated relative risk (RR) = 0.9, 95% confidence interval (CI) 0.7-1.2). These results suggest that an induced abortion, if followed at some later time by pregnancy and childbirth, does not increase a woman's risk of breast cancer.     

Breast cancer in relation to the occurrence and time of induced and spontaneous abortion

The authors evaluated whether an induced or spontaneous abortion during the first six months of gestation, particularly if it occurs before the first term pregnancy, increases the risk of breast cancer. Data from a case-control study of women under 70 years of age were used: 3,200 cases of breast cancer were compared with 4,844 controls with nonmalignant nongynecologic conditions. Among both nulliparous and parous women, the risk of breast cancer was not related to the number of induced or spontaneous abortions. After allowance for all identified potential confounding factors, the estimated relative risk for nulliparous women with an induced abortion relative to those who had never been pregnant was 1.3 (95% confidence interval (CI) 0.8-2.2), and for spontaneous abortion, the corresponding estimate was 0.9 (95% CI 0.5-1.5). Among parous women, the estimated relative risks were 1.2 (95% CI 0.9-1.6) for an induced abortion and 0.9 (95% CI 0.8-1.0) for a spontaneous abortion, relative to never having had an abortion of any type. The time of the abortion had little effect: The relative risk estimates were 0.9 (95% CI 0.5-1.4) for induced abortion before the first term birth, 1.4 (95% CI 1.0-1.9) for induced abortion first occurring after the first term birth, 0.9 (95% CI 0.7-1.2) for spontaneous abortion before the first term birth, and 0.9 (95% CI 0.7-1.0) for spontaneous abortion first occurring after the first term birth. Similar results were evident for women under age 40, among whom the frequency of induced abortion was relatively high. These data suggest that the risk of breast cancer is not materially affected by abortion, regardless of whether it occurs before or after the first term birth.     

Reproductive history and the risk of neonatal sepsis

Summary. It was recently suggested that a previous abortion increases the risk of intrapartum infection in a following pregnancy. The authors hypothesised that abortion also could be associated with a higher risk of neonatal sepsis. A case-control study of neonatal sepsis was conducted using the Washington State Birth Registry. Cases of sepsis were selected among singleton livebirths during the period 1984-90, and compared with a control group for the occurrence of spontaneous or induced abortion in previous pregnancies. The risk estimates were calculated using a stratified analysis. After exclusion of primigravidae, the age-adjusted odds ratio (OR) was 1.68, with a 95% confidence interval (CI) 1.33,2.11 for previous spontaneous abortion, and 2.20 (95% CI 1.73, 2.79) for induced abortion, compared with previous livebirth. After exclusion of nullipa-rous women, the OR decreased to 1.19 (95% CI 0.90,1.58) for spontaneous abortion and 1.45 (95% CI 1.03, 2.04) for induced abortion. After controlling for the effect of parity, induced abortion is associated with an increased risk of neonatal sepsis in a subsequent pregnancy, but the association between spontaneous abortion and sepsis is small and nonsignificant. The authors suggest that the procedures involved in a therapeutic abortion might produce a latent, sub-clinical infection that persists until the next pregnancy, and is then transmitted to the newborn.